The Cool Thing About Heat Pumps
Heat pumps are having a moment. With increasing calls to reduce dependency on fossil-fuels and accelerate the use of clean technologies, the electric heat pump is getting a renewed boost in the portfolio of existing low-carbon technology. In 2022, Americans installed 4 million heat pumps, beating out fossil-fuel powered gas furnaces for the first time. The European Heat Pump Association reported a 38% spike in heat pumps sales in 2022 compared to the year before. Technology trades have been featuring heat pumps as an efficient, electric alternative to fossil-fuel systems. There was even a panel on heat pumps at South by Southwest this year.
It’s also left a lot of people wondering why this technology isn’t more widely used – and what makes heat pumps a significantly more efficient way to heat and cool buildings.
According to the International Energy Agency, in 2022 electric heat pumps met only 10% of heating needs in buildings globally. But they are capable of supplying more than 90% of global space and water heating at a lower CO2 emissions level when compared to condensing gas boiler technology.
While the public profile of heat pumps may be getting renewed interest, the technology has been used since the 1950s, with significant performance improvements along the way.
Moving and removing heat - naturally
Don’t let the name fool you – heat pumps don’t actually create heat. They get their name from the process of extracting and exchanging existing heat from one place to another.
Here’s a simple explanation of how they work:
When it’s cold outside and you want to heat your home, an electric heat pump pulls heat from the outside air and transforms it into a gas where it is compressed and heated to the desired indoor temperature. A fan is used to disperse the heat into your home.
Conversely, when it’s hot outside and you want to cool your home, the process reverses, pulling heat from indoors and transferring it outside, lowering the temperature of your home – in essence, cooling it.
Beyond homes, heat pumps can be used in much larger applications, like commercial and industrial spaces where they can heat and cool the air. Even more advanced systems can also heat and cool water for other uses, like bathroom showers or manufacturing processes requiring chilling or hot water.
While most heat pumps transfer heat from the air, like the example above, there are geothermal-heat pumps that draw heat from the ground, and water-source pumps that pull heat from nearby water sources, including processes like wastewater management.
A built-in lower-carbon footprint
There are multiple reasons that heat pumps are a lower-carbon alternative to traditional electric and gas-powered heating and cooling.
Heat pumps are powered by electricity and recovered energy.
Any heat released into the environment can be considered wasted – and since it takes energy to produce heat, wasted heat is wasted energy. Because heat pumps extract dormant heat, their ability to recover and reuse heat makes them a powerful resource in the ‘free energy’ sector.
Take for instance data centers that power the internet as we know it. These clusters of servers produce an abundance of residual heat and require significant cooling. In the Alsameer Energy Hub in The Netherlands, excess heat from a local data center was captured and transferred via heated water to three neighboring locations, including a school and gym. Chilled water from those same facilities returned to the datacenter – providing its necessary cooling requirements. Thanks to heat pumps combined with other thermal management technology, this energy transfer delivered a lower base temperature at the data center, helped to significantly reduce the electricity needed to create an optimal temperature within the facility and the energy needed to heat water for the school and gym.
Even in cases where the direct energy source of a heat pump is a carbon-burning electrical grid, conservative estimates put electricity demands of a heat pump down by 30 to 40 percent. When paired with renewable energy sources, like solar, modern heat-pumps have the potential to become zero carbon solutions.
Heat pumps are extremely efficient.
Historically heating and cooling were approached separately given the technology available at the time.
Advanced technology like heat pumps allow us to combine independent heating and cooling systems, resulting in impressive energy efficiency gains. When compared to conventional heating and cooling technologies, efficiency performance can increase by over 300%. In some instances, high-efficiency heat pumps can actually create their own internal energy, requiring even less units of energy from a direct power source.
Scaling up with heat pumps
All climates
Thanks to technological advancements that have improved performance of electric heat-pumps in geographies with sustained sub-freezing temperatures, a resurgence is catching on with adoption in even some of the coldest climates on earth, like Finland. In fact, 60% of homes in Norway are equipped with heat pumps. The key feature allowing this ultra-cold performance is an advance in variable speed inverter-driven compressor technology, which wasn’t available in mainstream residential offerings just a decade ago.
Late last year, Trane Technologies surpassed the U.S. Department of Energy’s Cold Climate Heat Pump Challenge (CCHP) for high-efficiency residential heating in freezing temperatures. When tested at the DOE’s lab, Trane’s CCHP prototype performed in temperatures as low as negative 23 degrees Fahrenheit, surpassing the mandatory negative 20 degrees Fahrenheit DOE requirement.
When outdoor temperatures get very low and efficiency dips below desired levels, heat pumps can also be paired with other sources for a dual-fuel or hybrid arrangement that provides back-up capacity.
Good for both new and old buildings
For a large part of the world, replacing old systems involves retrofitting buildings with new technology. Since construction in older, more dense urban settings presents a unique set of challenges, custom district heating schemes can be an important solution in the future of urban comfort heating and cooling.
In one example in Geneva, Switzerland, a major district heating solution is using a thermal network to heat and cool buildings in and around the city center with water from the lake, growing from an initial footprint of 50 buildings in 2018 to a goal to expand to over 350 buildings by 2035.
Pressure to transition
Challenges to quickly accelerate deployment of heat pumps do exist. In many European countries, heat pumps are highly subsidized due to a strong focus on environmental sustainability. Through its REPowerEU initiative, the European Union wants 30 million new heat pumps installed by 2030, saying this could save the EU 35 billion cubic meters (bcm) in gas consumption per year.
In the U.S., climate policy has been less consistent, though electrification regulations for buildings are gaining traction in more and more states, from California to Massachusetts, which will help heat pump markets grow. Additional climate provisions, like those introduced in the Inflation Reduction Act of 2022, will help accelerate the use of clean technology like heat pumps in energy-intense infrastructure and systems, while encouraging even more innovation.
Even as more heat pumps enter the market, from residential applications to much larger opportunities in commercial spaces, to reap their full decarbonizing potential, power grids must get greener. Coal-fired plants are still prevalent in some of the world’s largest developed and developing economies, including China, the U.S. and India. There is progress, however – 40 countries committed to phase out their coal power plants at the COP26 summit.
In the meantime, the heat pump is finally gaining recognition as a ready solution to reduce energy costs and consumption, lower carbon emissions, and decrease dependence on fossil fuels.
To learn more, explore our infographic below or read our white paper focused on commercial solutions, Trane©: The Future of Heating is Electric.
